CDC25A (also known as cell division cycle 25 homolog A) is a member of the CDC25 family of phosphatases that are required for progression from G1 to the S phase of the cell cycle. CDC25A can activate the cyclin-dependent kinase CDC2 (also known as CDK1) by removing two phosphate groups. CDC25A is specifically degraded in response to DNA damage, which prevents cells with chromosomal abnormalities from progressing through cell division. CDC25A overexpression is detected in human cancers and this may contribute to the tumorigenesis process. CDC25A is degraded by moderate heat shock and this degradation is protected by HSP90.